The origin of the name "SAO" is unclear. A widely held belief is that the name is an acronym for "Salvation Army Officer", and was named for Arthur, one of the Arnott brothers, who was indeed an officer in the Salvation Army. The Salvation Army Australia somewhat cautiously mentions this on its website, calling it "Arguably Fact" and saying "...it is understood they named it in honour of their brother Arthur Arnott, a Salvation Army Officer.[2] In the 1993 book The Story of Arnott's Famous Biscuits, Ross Arnott states that Sao was the name of a sailing boat which his grandfather [Arnott's founder William Arnott] saw on Lake Macquarie, of which he said "That would make a good name for a biscuit."[3]

SAOs were also one of the first biscuits to be heavily advertised in magazines and newspapers in the early part of the 1900s. In the 1960s, the famous[citation needed] SAO song was launched. SAOs light texture is achieved by rolling the dough into thin sheets, then carefully layering it to give distinctive bubbles and crumbs.

SAOs are often eaten as a light snack, topped with butter/margarine and Vegemite, or other ingredients.

Traditionally, Arnott's delivery vans have had number plates in the range SA 0nn in recognition of the SAO brand.